(a) Field of the Invention
The present invention relates to a liquid crystal display.
(b) Description of the Related Art
A liquid crystal display includes a common electrode panel having a common electrode, and a thin film transistor array panel having a thin film transistor array. The common electrode panel and the thin film transistor array panel face to each other and are combined to each other by a seal line formed between the two panels, and a liquid crystal layer is formed in the space therebetween. This liquid crystal display including the two panels is provided with field-generating electrodes, and the liquid crystal layer interposed therebetween, and displays images by applying voltages to the field-generating electrodes to generate an electric field in the liquid crystal layer that determines the orientations of liquid crystal molecules therein to control the amount of transmitted light.
Because the liquid crystal display is a non-emissive device, a backlight unit for providing the light on the rear of the thin film transistor array panel is provided. On the other hand, a reflector may be disposed on the thin film transistors for using light that is incident from the outside on the thin film transistor panel. The amount of transmittance of light that is irradiated by a backlight or incident from the outside is controlled according to the arrangement of the liquid crystal molecules.
The thin film transistor array panel includes a plurality of gate lines, data lines, and pixel electrodes. The gate lines extend in the row direction and transmit gate signals, and the data lines extend in the column direction and transmit data signals. The pixels are connected to the gate lines and the data lines, and to a plurality of switching elements and storage capacitors.
Here, the switching elements are disposed at portions where the gate lines and the data lines intersect each other, and each switching element is a three terminal element including a control terminal connected to a gate line, an input terminal connected to a data line, and an output terminal connected to a pixel electrode. The output terminal of each switching element is connected to the storage capacitor and the liquid crystal capacitor.
In the case of the general liquid crystal display, the pixel electrodes are disposed on the data lines to improve the aperture ratio, and a low dielectric organic layer is formed between the pixel electrodes and the data lines to reduce parasitic capacitance generated therebetween.
However, there is a limitation in reducing the parasitic capacitance by using the low dielectric organic layer. Particularly, because the liquid crystal display is adjusted to line inversion driving or dot inversion driving, opposite voltages are applied to neighboring pixel electrodes. Accordingly, when the data lines are disposed under the pixel electrodes to improve the aperture ratio, if a difference between the potential of pixel electrodes disposed on both sides of a data line and the voltage applied to the data line is increased, the parasitic capacitance generated by the coupling effect between the data line and the pixel electrodes is particularly increased. Typically, a greenish phenomenon occurs. This is a defect in which the gamma values of the yellow colors are decreased when the yellow-based color is displayed on the entire screen such that green colors appear. This depends on differences between the voltage applied to the data line and the substantial pixel voltage due to the increase of a load of the data line according to the parasitic capacitance.
Furthermore, a black matrix is disposed on the common electrode panel corresponding to the data lines to prevent light leakage generated at the edge of the data lines. Light emitted from a backlight disposed under the thin film transistor array panel is incident to the data lines with diverse angles and is reflected by the data lines at a large angle such that the light leakage is generated. To prevent the light leakage, it is necessary to increase the area of the black matrix. However, if the area of the black matrix is increased, the aperture ratio of the liquid crystal display is decreased and the light leakage is reduced, but the luminance of the liquid crystal display is reduced.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.